Conventionally, a mail finishing system, such as an inserter machine for inserting collations of documents into envelopes to create finished items of mail has been under control of an inserter system controller, which may form an integral part of the inserter machine. Data generated by the inserter system controller is passed to the secure accounting system so that the secure accounting system may generate accounting data relating to the items of mail produced by the mail finishing system. The data passed by the inserter system controller to the secure accounting system typically comprises information concerning the weight and postage value of items of mail generated by the mail finishing system, as well as the number of items of mail in a batch of mail. On the basis of this information, the secure accounting system maintains a record of postage value dispensed in relation to the items of mail generated by the mail finishing system. But there may be instances where the secure accounting system is unable to process the information received from the mail finishing system.